1. Field of the Invention
The present invention relates to a waterproof-seal inserting apparatus for applying a waterproof seal to an end portion of an electric wire.
2. Description of the Background Art
Conventionally, an apparatus for processing an electric wire, which applies a tube-shaped waterproof seal made of a rubber or the like to an end portion of the electric wire and crimps a terminal to the end portion of the electric wire, has been devised. The conventional apparatus for processing an electric wire includes a dimension measuring unit, a front cramp, a cutter unit, a rear cramp, a front seal-feeding mechanism, a front seal-inserting mechanism, a front terminal-crimping unit, a rear seal-feeding mechanism, a rear seal-inserting mechanism, a rear terminal-crimping unit, a front moving member, and a rear moving member, for example.
The conventional apparatus for processing an electric wire has a structure in which each of the seal-feeding mechanisms is placed on a separate stand different from a stand on which a body of the apparatus is placed, in order to allow stable feeding of waterproof seals and improve versatility in installation, in some cases. In the foregoing structure, waterproof seals are fed from the seal-feeding mechanisms to the seal-inserting mechanisms through seal feeding tubes using air which serves to feed waterproof seals (“feeding air”) (see Japanese Patent Application Laid-Open No. 11-345668, which will be hereinafter referred to as “JP No. 11-3456668”, for example).
Then, a predetermined amount of electric wire which is fed along a line for feeding an electric wire (“electric-wire feeding line”) is grasped by the front cramp and the rear cramp. Subsequently, the electric wire is cut by the cutter unit, to be divided into two parts which are grasped by the front cramp and the rear cramp, respectively.
Next, one part out of the two parts of the electric wire which is grasped by the front cramp is moved to a position where the front seal-inserting mechanism is placed. The front seal-inserting mechanism receives waterproof seals which are sequentially fed from the front seal-feeding mechanism. In the position where the front seal-inserting mechanism is placed, an end portion of the one part of the electric wire is inserted into one of the waterproof seals received from the front seal-inserting mechanism, and is fitted in the waterproof seal, so that the waterproof seal is mounted to the end portion of the one part of the electric wire.
Thereafter, the one part of the electric wire is returned back to a position where the cutter unit is placed. In the position where the cutter unit is placed, a covering of a portion of the one part of the electric wire, which portion is located closer to an end than a portion mounted by the waterproof seal, is stripped off by the cutter unit, so that a core of the one part of the electric wire is exposed.
After the covering is stripped off, the one part of the electric wire is moved to a position where the front terminal-crimping unit is placed. In the position where the front terminal-crimping unit is placed, a terminal is crimped onto the portion whose covering has been stripped off, by the front terminal-crimping unit.
After the terminal is crimped onto the one part of the electric wire crimped, the one part of the electric wire is driven to be located to a position where the one part of the electric wire faces the cutter unit, by the front moving member. Then, a predetermined amount of electric wire is further fed in a predetermined direction along the electric-wire feeding line by the dimension measuring unit.
Thereafter, the electric wire which is further fed is grasped by the front cramp and the rear cramp, and cut by the cutter unit, to be divided into two parts grasped by the front cramp and the rear cramp, respectively. Thereafter, the same processes as described above are performed on an end portion of one part out of the two parts of the electric wire which is grasped by the front cramp, so that a terminal is crimped onto the one part of the electric wire.
On the other hand, the other part of the electric wire which is grasped by the rear cramp, is moved to a position where the rear seal-inserting mechanism is placed. The rear seal-inserting mechanism receives waterproof seals which are sequentially fed from the rear seal-feeding mechanism. In the position where the rear seal-inserting mechanism is placed, an end portion of the other part of the electric wire is fitted in the waterproof seal, so that the waterproof seal is mounted to the end portion of the other part of the electric wire, in the same manner as described above.
Thereafter, the other part of the electric wire is returned back to the position where the cutter unit is placed. In the position where the cutter unit is placed, a covering of a portion of the other part of the electric wire, which portion is located closer to an end than a portion mounted by the waterproof seal, is stripped off by the cutter unit, so that a core of the other part of the electric wire is exposed.
After the covering is stripped off, the other part of the electric wire is moved to a position where the rear terminal-crimping unit is placed. In the position where the rear terminal-crimping unit is placed, a terminal is crimped onto the portion whose covering has been stripped off, by the rear terminal-crimping unit.
After the terminal is crimped onto the other part of the electric wire, the other part of the electric wire is discharged into a preset electric-wire storage by a discharging member, and the rear cramp is driven to be located back to a position where the rear cramp faces the cutter unit by the rear moving member. In this manner, harnesses each having opposite ends to which waterproof seals are applied and terminals are crimped are sequentially manufactured by the conventional apparatus.
However, the above-described conventional apparatus disclosed in the JP No. 11-345668 employs a method in which a waterproof seal is fed directly to a recess of a seal holder, into which the waterproof seal is fit (“seal acceptance recess”) in the seal-inserting mechanism, from the seal-feeding mechanism through the seal feeding tube using feeding air. In this method, an end portion of an electric wire is supposed to be inserted into a waterproof seal which is being fit in the seal acceptance recess of the seal holder.
Accordingly, after the waterproof seal is applied to the end portion of the electric wire and the waterproof seal comes off the seal acceptance recess of the seal holder so that no waterproof seal exists in the seal acceptance recess, a next waterproof seal is fed from the seal-feeding mechanism located at some distance from the seal-inserting mechanism, through the seal feeding tube, to be applied to an end portion of a next electric wire. Thus, the next electric wire must stand by for a longer time before the next waterproof seal arrives, to impose limitation on a processing speed.
Also, in fitting a waterproof seal which is fed through the seal feeding tube into the seal acceptance recess of the seal holder, an air pressure is used. This likely causes variation in a position where a waterproof seal is fit, and thus the conventional apparatus is not reliable in that it is difficult to fit a waterproof seal in a desired position in the seal acceptance recess.